Chore: Add grafana-apiserver (#70721)

* add grafana-apiserver
* remove watchset & move provisioning and http server to background
services
* remove scheme
* otel fixes (#70874)
* remove module ProvideRegistry test
* use certgenerator from apiserver package
* Control collector/pdata from going to v1.0.0-rc8 (as Tempo 1.5.1 would have it)

pkg/modules/modules.go

@@ -3,11 +3,13 @@ package modules
 import (
 	"context"
 	"errors"
+	"fmt"
 
 	"github.com/grafana/dskit/modules"
 	"github.com/grafana/dskit/services"
 
 	"github.com/grafana/grafana/pkg/infra/log"
+	"github.com/grafana/grafana/pkg/services/featuremgmt"
 	"github.com/grafana/grafana/pkg/setting"
 	"github.com/grafana/grafana/pkg/systemd"
 )
@@ -35,9 +37,14 @@ type service struct {
 	moduleManager  *modules.Manager
 	serviceManager *services.Manager
 	serviceMap     map[string]services.Service
+
+	features *featuremgmt.FeatureManager
 }
 
-func ProvideService(cfg *setting.Cfg) *service {
+func ProvideService(
+	cfg *setting.Cfg,
+	features *featuremgmt.FeatureManager,
+) *service {
 	logger := log.New("modules")
 
 	return &service{
@@ -47,6 +54,8 @@ func ProvideService(cfg *setting.Cfg) *service {
 
 		moduleManager: modules.NewManager(logger),
 		serviceMap:    map[string]services.Service{},
+
+		features: features,
 	}
 }
 
@@ -54,6 +63,11 @@ func ProvideService(cfg *setting.Cfg) *service {
 func (m *service) Init(_ context.Context) error {
 	var err error
 
+	if err = m.processFeatureFlags(); err != nil {
+		return err
+	}
+
+	m.log.Debug("Initializing module manager", "targets", m.targets)
 	for mod, targets := range dependencyMap {
 		if err := m.moduleManager.AddDependency(mod, targets...); err != nil {
 			return err
@@ -93,6 +107,7 @@ func (m *service) Run(ctx context.Context) error {
 	listener := newServiceListener(m.log, m)
 	m.serviceManager.AddListener(listener)
 
+	m.log.Debug("Starting module service manager")
 	// wait until a service fails or stop signal was received
 	err := m.serviceManager.StartAsync(ctx)
 	if err != nil {
@@ -149,3 +164,31 @@ func (m *service) RegisterInvisibleModule(name string, initFn func() (services.S
 func (m *service) IsModuleEnabled(name string) bool {
 	return stringsContain(m.targets, name)
 }
+
+// processFeatureFlags adds or removes targets based on feature flags.
+func (m *service) processFeatureFlags() error {
+	// add GrafanaAPIServer to targets if feature is enabled
+	if m.features.IsEnabled(featuremgmt.FlagGrafanaAPIServer) {
+		m.targets = append(m.targets, GrafanaAPIServer)
+	}
+
+	if !m.features.IsEnabled(featuremgmt.FlagGrafanaAPIServer) {
+		// error if GrafanaAPIServer is in targets
+		for _, t := range m.targets {
+			if t == GrafanaAPIServer {
+				return fmt.Errorf("feature flag %s is disabled, but target %s is still enabled", featuremgmt.FlagGrafanaAPIServer, GrafanaAPIServer)
+			}
+		}
+
+		// error if GrafanaAPIServer is a dependency of a target
+		for parent, targets := range dependencyMap {
+			for _, t := range targets {
+				if t == GrafanaAPIServer && m.IsModuleEnabled(parent) {
+					return fmt.Errorf("feature flag %s is disabled, but target %s is enabled with dependency on %s", featuremgmt.FlagGrafanaAPIServer, parent, GrafanaAPIServer)
+				}
+			}
+		}
+	}
+
+	return nil
+}